Valeraldehyde

The odor pairs were a natural odor pair (curry powder vs. cinnamon) or a pair of pure monomolecular odorants (ethyl butyrate, valeraldehyde, isoamyl acetate, ethyl tiglate, hexanone or cineole, Sigma-Aldrich). Pure odorants were diluted 1:10 in 10 mL mineral oil and natural odorants were presented in their native state. Saturated odor vapor was further diluted with humidified clean air (1:10) by means of computer-controlled solenoid pinch valves. Odor presentation was performed using a custom-built computer interface. Odor delivery dynamics were monitored and calibrated using a mini-PID (Aurora). Odors were delivered randomly within a block (10 trials of each odorant).

Valeraldehyde, ethylenediamine, and triphenylphosphite were provided by Sigma-Aldrich (Saint-Louis, MO, USA). Fluka AG (Buchs, Switzerland) provided acetonitrile and lithium perchlorate. All reagents were used exactly as they were given without any purification.
For the corrosion rate measurements, mild carbon steel sheet samples with chemical composition (in wt. %): 0.243 C, 0.028 P, 0.0036 Si, 0.320 Mn, and the balance Fe were used. The surface area of each sample was about 6 cm⁻² (for weight loss tests) and 0.354 cm² (for electrochemistry tests). The samples were repeatedly polished with fine-grade emery sheets, disinfected with acetone, cleaned doubly with distilled water, and dried [32 (link)].